Increased CD10/TdT positive cells in the bone marrow of an infant with immune thrombocytopenia.

We describe the case of an infant with immune thrombocytopenia whose bone marrow showed an increased percentage of CD10/TdT-positive lymphoid cells that resembled the onset of an acute lymphoproliferative disorder. Genotypic analysis of bone marrow, however, failed to reveal the malignant origin of these B cell precursors. After 8 months of follow-up, the child is alive and well, and shows a chronic form of ITP. Although a relation between this B cell proliferation and the onset of ITP cannot be excluded, it is important to consider this atypical pattern as a benign hematologic condition.